When the mighty angel speaks, his words are like the roar of a lion and he is answered by “the seven thunders.” The angel speaks, John hears the response from the seven thunders, but he is forbidden to write these words. Why are the words of this mighty not recorded? Possibly this means the angel’s words were unintelligible (2 Cor 12:4; Betz, TDNT 9:296).
The “roar” of the Lord is a somewhat common motif in the Old Testament. Just prior to Moses receiving the Law at Mount Sinai, the people gather around the foot of the mountain and witness thunders (plural) and lightning as well as a “very loud trumpet blast” (Exodus 19:16). Later Rabbinic literature interpreted these thunders as the voice of God. The voice was so loud all the people of the world heard the voice, and “God’s voice split up into 70 voices acc. to the 70 languages of the earth, so that each people could hear it in its own tongue” (Betz, TDNT, 9: 288). Psalm 29:3-9 a seven-fold description of the voice of God as thunder, although the word “voice” is not there seven times. There is a rabbinic tradition that the voice of God was heard as seen thunders on Mt. Sinai (Exod. Rab. 28:6, cf. 5:9.
Since the lion of Judah appears in Revelation 5:5, perhaps a voice like thunder is drawn from the metaphor of the thunderous voice of a lion. For example, Amos 1:2 begins with the words, “The LORD roars from Zion and thunders from Jerusalem.” Joe alludes to this text: The Lord “will roar from Zion and thunder from Jerusalem” (3:16). The voice of God as thunder is common in other apocalyptic literature as well, “the One who thunders on high” (Sibylline Oracles 5.302). In 4 Ezra 16.10, the Lord is like a hungry lion who thunders and terrifies everyone.
Aune suggests thunder is a common “metaphor for articulate speech by supernatural beings” in both Jewish apocalyptic and Greek magical papyri (2:560). In Sibylline Oracles 5.344–345, “It will be possible to hear a heavenly crash of thunder, the voice of God throughout broad heaven above.” The “voice of the thunder” and the light of the lightning” are kept in the heavens (1 Enoch 69.23). In 2 Enoch 39.7 Enoch claims he has “heard the LORD speaking like loud thunder.” In the mystical visions of 3 Enoch, the writer “saw thunders and voices roaring in the midst of flames of fire” (3 Enoch 42.5)
In an example of a heavenly tour, Enoch is shown the secrets of the thunders:
1 Enoch 59:1-3 In those days, my eyes saw the mysteries of lightnings, and of lights, and their judgments; they flash lights for a blessing or a curse, according to the will of the Lord of the Spirits. 2 And there I (also) saw the secrets of the thunder and the secrets of (how when) it resounds in the heights of heaven its voice is heard (in) the earthly dwellings. He showed me whether the sound of the thunder is for peace and blessing or for a curse, according to the word of the Lord of the Spirits. 3 After that, all the mysteries of the lights and lightnings were shown to me (that) they glow with light for blessing and for contentment.
John prepared to write the content of the words spoken by the thunders but a “voice from heaven” prevents him. He is told to seal up the vision and not write it down. In Daniel 12:9 Daniel could not understand the angel’s explanation of his vision and he is told “the words are to remain secret and sealed until the time of the end.” On the other hand, Enoch was permitted to write down “the rumble of the thunder and the lightning” (2 Enoch 40.9).
Keeping secrets is common in Jewish apocalyptic literature. In 1 Enoch 49, for example, Enoch is shown “all the secrets in heaven.” The reason for this, as Aune suggests is that the visionary alone knows the secrets. This makes him wise and different than the reader. It was a mark of authenticity to hold back a little revelation from the readers, if you gave it all then perhaps there were skeptics.
What did the seven thunders say? Bousset suggested John was given another series of plague judgments like the seals, trumpets, and bowls, and that he was told not to record this series (cited by Aune 2:5620). This is certainly possible, and if so, indicates that there will be more judgements during the tribulation happening than could expected after reading Revelation. Leviticus 26 has four seven-fold plagues as a part of the curses and blessings in Leviticus (26:18, 21, 23, and 27). This would mean there were four sets of seven judgments, one set was set aside. Caird suggested the reason John is told not to record the content of the visions is because God will cancel these judgments out of his grace and mercy (Caird, 126-127). But as Beale points out, “seal up” does not have the same sense as “cancel” (Beale 535).